Spreader for knit fabrics for use on circular knitting machines



F. SEILER Nov. 23, 1965 SPREADER FOR KNIT FABRICS FOR USE ON CIRCULAR KNITTING MACHINES 2 Sheets-Sheet 1 Filed Sept. 24, 1963 ,V7C J WI ATTORNEYS Nov. 23, 1965 F. SEILER 3,218,829

SPREADER FOR KNIT FABRICS FOR USE ON CIRCULAR KNITTING MACHINES Filed Sept. 24, 1963 2 Sheets-Sheet z INVENTOR air: 5 E |L ER 7 MW /Q7WL/ ATTOR NEXS United States Patent 3,218,829 SPREADER FOR KNIT FABRICS FOR USE ON CIRCULAR KNITTING MACHENES Fritz Seiler, Corcelles, Neuchatel, Switzerland, assignor to Edouard Dubied et Cie. ocit Anonyrne) Couvet, Neucllatel, Switzerland Filed Sept. 24, 1953, Ser. No. 311,022 Claims priority, application Switzerland, Sept. 26, 1962, 11,362/ 62 3 Claims. (Cl. 66-147) In circular knitting machines the fabric produced by the needles of the cylinder or/and the dial normally has the shape of tubular hose which descends, in most of the machines used in the knitting industry, inside of the hollow cylinder. This lowering of the fabric is produced by a suitable fabric pulling device, comprising stretching or draw-01f rollers as principal components for producing the downward travel of the knitted fabric about, or between which rollers the fabric is advanced by friction or adherence.

The majority of known constructions use two parallel rollers, having a diameter which is generally determined by the required resistance against bending. One of these two rollers is normally rotatable about an axle having a fixed center, and is rotated at the required speed by suitable driving means. The other roller is rotatably mounted on an axle having a movable center, which is adapted to be radially displaceable and to be driven by the first roller by gear means. Moreover, the movable roller is pressed against the fixed roller by springs.

In order that the tubular fabric can pass between said two parallel rollers, it is necessary to flatten it. Thus, assuming that there are then two longitudinal and oppositely located folds in the fabric, a fiat double web is obtained. However, the transition from the tubular shape to the flat shape cannot be effected without assistance, because the traction exerted on the fabric by the draw-off rollers then is no longer uniform along the periphery of the tube. This disadvantage may be removed, if not entirely, at least in a practically satisfactory manner, by using a stretcher (or spreader) for the knit goods, of which several types are known.

The production of a fabric having the shape of a tube presupposes the absence of any solid obstacle in the path of the downwardly moving fabric. Therefore, in a circular knitting machine having a cylinder and a plate forming the needle beds, the provision of a direct rigid connection between these elements, inside of the cylinder, that is in the space traversed by the tubular fabric, is not possible. The mechanical connection without play, which is indispensable for the rigorously synchronized rotation of both needle-beds, accordingly is realized by suitable means disposed outside of the needle-beds. Such devices (circular, conical or worm gears) generally are very cumbersome and heavy, and since they have to be made and mounted With the highest precision, very expensive.

In order to eliminate these disadvantages, there has recently been proposed a circular knitting machine of this type in which the cylinder and the dial are directly connected one to the other inside of the cylinder, in an absolutely rigid manner, requiring little space, and which is of relatively cheap construction. This device is disclosed for example in the German patent specification No. 1,103,505. It is obvious that this direct connection between the cylinder and the dial requires continuous longitudinal slitting of the tubular fabric, so that it, when gradually moving downwards, may pass to the left and right side of said rigid connection. The above mentioned patent specification therefore includes the description of a suitable cutting or slitting means for the fabric.

3,218,829 Patented Nov. 23, 1965 However, the result of such a continuous incision is that the considerable circumferential tension in the tubular fabric, due to the oblique direction of the numerous loop threads forming the fabric, has the tendency to disappear immediately. In fact, since the equilibrium of the forces is distributed by the vertical cut, the production of a lateral slackening towards the intact periphery of the fabric is inevitable. In other words, both edges produced by the incision do not maintain their mutual distance apart corresponding to the thickness of the cutting element, nor do they remain in vertical alignment with the lowering direction of the fabric. On the contrary, they will spread apart as soon as the cut is made and will assume oppositely oblique directions with an angle of inclination up to 45 on both sides of the cutting means. Later on, that is when the circumferential slackening is achieved gradually with the downward progression of the fabric, the two edges will assume more and more a vertical position but they will be considerably spaced one from the other. Therefore the longitudinal opening in the fabric will not have the shape of a narrow parallel slit, but of a large ogive-like aperture.

In this condition, the fabric will arrive at the draw-off device. It can be introduced therein in two different man ners which are characterised by the relative position of the slit opening of the flattened tube with respect to the traction rollers. This opening can either be placed in the middle of the length of the rollers, so that the two opposed folds in the sheet are in the full portion of the fabric at the ends of the rollers, or another possibility is to have the cut edges coincide with one of the two folds of the flattened tube, the other fold then being in the middle of the full portion of the sheet. The opening in the fabric is situated in this case at One end of and between the two rollers. In practice, it is this latter solution which appears to be the most favourable and consequently, the following description will be based thereon. In either of these two variants the slackening produced in the cut fabric has a further unavoidable and undesirable result, namely the two edges of the cut opening will roll or coil up and Will then become squeezed between the two rollers. Furthermore, the traction exerted on the tubular fabric is not sufficiently effective in the zones of the fabric situated laterally along the cut. Consequently it will be necessary to restore in the fabric at least a part of its lost transverse tension by moving the two edges towards each other before they are inserted in between the two traction rollers, while retaining and guiding their outermost loops and bringing them together.

It is an object of the present invention to provide a stretching device with simple and efficient means, requiring little space, for effecting the correct traction of an open tubular fabric produced in a circular knitting machine having a direct and rigid connection between the cylinder and the dial inside of the cylinder. According to the invention, said stretching device comprises a plurality of pairs of inclined rotatable and cylindrical carding rollers adapted to produce owing to their rotation a transverse tension in the fabric sheet and to approach, unroll and guide the turned-up edges of the fabric on both sides of the cut opening.

Rotation of the carding rollers can be brought about by the progression of the fabric itself, without any special mechanical drive and the inclination of the carding rollers can be varied according to requirements.

The use of carding rollers in stretching devices for knitting machines and knitting frames is well known. But such carding rollers are exclusively used as pulling devices, and operate by linear displacement or by rotation. Accordingly, they are always driven and require complicated and expensive driving means.

The accompanying drawings illustrate by way of example a preferred embodiment of the invention.

FIGURE 1 is a front view of a stretching device with the needle beds of a circular knitting machine partially shown in section;

FIGURE 2 is a side view of the structure shown in FIGURE 1;

FIGURE 3 is a plan view and FIGURE 4 represents a rotatable carding roller element drawn to a larger scale.

The tubular fabric 1, produced in the usual manner by the needles of the cylinder 2 and the dial 3 of a circular knitting machine descends inside of the cylinder towards a draw-off device having rollers 4 and 5, which are positively rotated in conventional manner. The two rollers engage the double fabric web between themselves and feed it downwardly in the direction of the arrow T, whereby the fabric is subjected to considerable longitudinal tension which is indispensable for the correct formation of the loops at their place of origin 20.

Before the tube 1 in fiat condition, enters between the two rollers 4 and 5, it passes a fabric stretching device 6 which operates in conventional manner and is not further described here. In the embodiment shown the stretching device 6 comprises shaped steel tubes, but it could also be made of wood, plastic material or the like. In order to hold the stretching device in a determined position with respect to the rollers 4 and 5, it is suspended from a rigid connecting member 7 between the cylinder and the dial by means of an adjustable frame 8.

Several pairs of rotatable cylindrical carding rollers 9 are freely rotatable on journal pins 10 mounted in forks 11 at certain determined points of the upper portion of the stretching device. Each fork 11 is adjustably fixed so that the angle of inclination a of its axis relative to the horizontal can be varied by means of a screw 12 on a supporting means which can be either a double arm 13 with bevelled faces, or an individual clamping block 14 which is mounted by means of a screw 15 on a base plate 16. This plate and the arm 13 are both secured to the stretching device 6; however, the position of the arm longitudinally of the rollers can be adjusted as de sired, while the position of the plate is fixed.

The arm 13 which is aranged on the side of the fold 1b of the double web carries two inclined carding rollers 9, whereas the plate 16 which is arranged on the side of the opening 1a carries four carding rollers 9.

Besides the posibility of individual orientation of the carding rollers on their respective supports, the stretching device can be longitudinally adjusted by means of a series of holes in the telescopic central rod 17, in which split eye-pins 18 are lodged.

Due to the orientation of the rollers 4 and and of the stretching device 6 in the direction 1a-1b (openingfold), both carding rollers 9 mounted on the arm 13 assist in stretching the fabric laterally in this zone applying it closely to the contour of the stretching device.

The four carding rollers on the plate 16 attract the two flattened knitted webs on both sides of the opening In for again imparting to them the transverse tension which was lost after the cutting of the tubular fabric by means of the cutting member 19 (e.g. a razor blade) arranged at a certain distance from the needle bed jacks 20, but ahead of the rigid connection 7. On the other hand, the horizontal component resulting from the automatic rotation of the carding rollers in inclined position according to the angle 0:, moves the two edges of the opening 1a continuously towards the outside thus moving them one towards the other and unrolling the turned up edges, or even preventing almost completely any rolling up of the edges.

In this manner, the knitted web will be stretched again in all directions and the tubular part, before being cut is submitted to a practically uniform traction along the whole circumference thereof.

By modifying the angle of inclination of the carding rollers it is possible to vary the tension in the knitted web, which often is required owing to the diversity of knitting materials, the structure of the loops, the tightness of the knitted fabric, etc.

I claim:

1. A stretching device for knit fabrics, for use on circular knitting machines which produce tubular fabrics and which are provided with a cylinder and a dial and have a direct rigid connection between the cylinder and the dial arranged inside of the cylinder, and in which the tubular fabric progresses after being knitted and during its progression is cut lengthwise, at a point of its circumference immediately after the formation of its loops, said device comprising a plurality of pairs of angularly adjustable rotatable and cylindrical carding rollers whose angles of inclination relative to the horizontal may be varied and which are rotated during progression of the cut tubular fabric and which owing to their rotation, produce a transverse tension in the cut tubular fabric and move, unroll and guide the turned up edges of the cut tubular fabric on both sides of the cut opening.

2. A stretching device as claimed in claim 1, wherein the carding rollers are freely rotatable and wherein rotation of the said carding rollers is produced solely by the progression of the cut tubular fabric.

3. A stretching device as claimed in claim 1, in which the said angles of inclination of the carding rollers can be varied according to requirements.

References Cited by the Examiner UNITED STATES PATENTS 2,017,082 10/1935 Warren 66-153 2,751,768 6/1956 Lebocey 66-149 X FOREIGN PATENTS 1,103,505 3/1961 Germany DONALD W. PARKER, Primary Examiner.

RUSSELL C. MADER, Examiner. 

1. A STRETCHING DEVICE FOR KNIT FABRICS, FOR USE ON CIRCULAR KNITTING MACHINES WHICH PRODUCE TUBULAR FABRICS AND WHICH ARE PROVIDED WITH A CYLINDER AND A DIAL AND HAVE A DIRECT RIGID CONNECTION BETWEEN THE CYLINDER AND THE DIAL ARRANGED INSIDE OF THE CYLINDER, AND IN WHICH THE TUBULAR FABRIC PROGRESSES AFTER BEING KNITTED AND DURING ITS PROGRESSION IS CUT LENGTHWISE, AT A POINT OF ITS CIRCUMFERENCE IMMEDIATELY AFTER THE FORMATION OF ITS LOOPS, SAID DEVICE COMPRISING A PLURALITY OF PAIRS OF ANGULARLY ADJUSTABLE ROTATABLE AND CYLINDRICAL CARDING ROLLERS WHOSE ANGLES OF INCLINATION RELATIVE TO THE HORIZONTAL MAY BE VARIED AND WHICH ARE ROTATED DURING PROGRESSION OF THE CUT TUBULAR FABRIC AND WHICH OWING TO THEIR ROTATION, PRODUCE A TRANSVERSE TENSION IN THE CUT TUBULAR FABRIC AND MOVE, UNROLL AND GUIDE THE TURNED UP EDGES OF THE CUT TUBULAR FABRIC ON BOTH SIDES OF THE CUT OPENING. 